Universal Mobile Telecommunications System (UMTS) is a 3rd Generation (3G) system based on a Wideband Code Division Multiple Access (WCDMA) air interface technology. Generally, the UMTS is also known as a WCDMA system. In the UMTS system, the coverage areas of adjacent cells are overlapped, and seamless handover is provided through soft handover. The gain accomplished through Macro Diversity Combining (MDC) enhances the system capabilities in resisting interference.
With the development of mobile communication technologies, the 3G technologies are developing and evolving. High Speed Uplink Packet Access (HSUPA) is introduced in the 3rd Generation Partnership Project (3GPP) release 6 (R6). The HSUPA also supports the uplink macro diversity technology.
A brief process of implementing the MDC is: The mobile station in the soft handover communicates with multiple base stations through different air interface channels. For the uplink, multiple base stations receive the uplink user data in the code division channel of the mobile station. The uplink user data received by the base stations is sent to a Radio Network Controller (RNC) so that the data can be selected and combined. The RNC uses a frame reliability indicator provided for the outer loop power control to select preferred uplink user data, and sends the selected data to a core network.
The foregoing network architecture is based on the 3GPP of a version earlier than R6. In order to improve the lifecycle of the WCDMA and protect the existing investment of the operator, the 3GPP puts forward an Evolved High Speed Packet Access (E-HSPA) evolution. The E-HSPA aims to improve the spectrum efficiency on the existing R6 version, reduce the delay of the control plane and the user plane, be compatible with old systems, and evolve to the Long Term Evolution 3GPP (LTE)/System Architecture Evolution (SAE) system smoothly, including enhancement of the air interface performance and evolution of the Radio Access Network (RAN) architecture.
In the E-HSPA network, the RNC function is shifted to the NodeB+ (E-HSPA NodeB). The NodeB+ is directly connected with the core network through an IuPS interface.
In the E-HSPA network, a process of implementing the MDC is: The uplink MDC is implemented in the serving cell base station of the user; for data on all radio links in an active set, if the data received on the radio link corresponding to a non-serving cell base station is correct, the non-serving cell base station sends the uplink data to the serving cell base station. The serving cell base station performs MDC for the received uplink data, and sends the data to the core network. This solution is similar to implementation of the MDC in the RNC in the existing 3G system except that the location for implementing the MDC function changes from the RNC to the serving cell base station. If the uplink macro diversity is implemented on the serving cell base station (capable of the functions of a Serving RNC (SRNC)), communication is required between base stations. If all other soft handover base stations transmit uplink receiving data to the serving cell base station for macro diversity processing, the transmission at the interface between base stations is overloaded (the last mile transmission resources are not enough), and the user-plane delay occurs.
Therefore, no matter whether the HSUPA system or the E-HSPA is introduced, the foregoing solution is based on the prerequisite of implementing the MDC. Such a solution is not flexible. For example, if the operator expects to save transmission resources at the cost of reducing performance, the solution does not fulfill that expectation.
Nevertheless, the MDC may be omitted in the foregoing system to save the transmission resources between base stations. However, if the macro diversity is not implemented, the performance is deteriorated to some extent. Therefore, this solution is based on the prerequisite of not accomplishing the MDC gain, and reduces system performance to some extent.
In the process of developing the present invention, the inventor finds at least the following defects in the prior art: The MDC may be employed or not in the solution in the prior art, but it is not considered that the obtained gain is different for different services. Therefore, the solution in the prior art is unable to implement the MDC more flexibly according to the service features and improve the system performance.